Heavy infants run high risk of being obese later on

Babies who are born heavy and grow fast have a 150 percent chance of being overweight or obese by the time they are seven years old, a survey of more than 8,000 children in Hong Kong has shown.

Obesity has long been associated with a person's lifestyle and dietary habits, but the study shows it might just as well be dependent on "epigenetics" -- factors such as genes, and the eating habits and lifestyle of parents and grandparents, said researchers at the University of Hong Kong.

"You tend to assume it's just your lifestyle, but what people are realizing is it's not just what you are doing now, but what people have done in your family in the past," said Mary Schooling, assistant professor at the university's School of Public Health.
New born infants would be considered heavy if they weigh 3.65 kg (8 pounds) and over.

Excess weight and obesity pose major risks for chronic diseases such as diabetes, heart disease, hypertension, stroke and some forms of cancer.

Globally, more than 1 billion adults are overweight, of which 300 million are obese, said the World Health Organisation.

And the problem is not confined to advanced nations in the west. In China, Japan, certain African nations, Thailand, Malaysia, Singapore and Hong Kong, childhood obesity is on the rise. In China, 10 million children aged between 7 and 18 were overweight in 2000, up 28 times from 1985.

Some experts explain this using the "thrifty gene" theory. Assuming a frugal environment from as recent as the 1950s and 1960s, the Asian constitution is programmed to store fat. But faced with sudden affluence, it is less able to cope and the person ends up obese and assailed with health problems.

The west, however, adapted to an environment of plenty over a far longer period, starting with the industrial revolution from the mid 18th century.

TRACKING A GENERATION OF CHILDREN

More than 8,300 children born in April and May 1997 in Hong Kong are involved in the long-term study and researchers plan to monitor them for the rest of their lives.

The scientists tracked their development at birth, 3 months, 9 months, 36 months and 7 years.

About 800 children in the study are now overweight or obese.

Boys at 7 years with a body mass index of more than 17.9 are considered overweight, while a BMI of over 20.6 would be obese. For girls, a BMI of over 17.53 would be overweight and more than 20.5 obese.

"What we have shown here is that babies who are born big and who have grown fast have a higher risk of being overweight or obese at age 7," Schooling said.

"The key point is to make sure that babies grow at a reasonable rate. That can be achieved most effectively by ensuring they are breastfed."

Experts say breastfeeding helps prevent overfeeding. Schooling and colleague Gabriel Leung said a child's body size may well be dependent on a host of other factors. "It has to do with the mother's diet, her lifestyle, even the grandmother's living environment ... it has to do with the life course of your parents, grandparents," Leung said.

"Perhaps our grandparents lived in scarcity, they may have the biological imprint for the baby to prepare for scarcity. But there is excess now, and the human body has no time to prepare for this change ... that's why our diabetes rate is so high."

The researchers plan to interview parents and grandparents of the group children to see if their body sizes are linked to dietary and lifestyle habits of the older generations.

Further ahead, these children would be monitored for health problems that tend to appear later in life, such as high blood pressure and diabetes.